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1. Stable recurrent calculation of isotropic Gaussian filter coefficients

Author:
Piretzidis, Dimitrios; Sideris, Michael G.
Source:
Computers & geosciences 2019
ISSN:
0098-3004
Subject:
gravity,   etc   ; computers; isotropy;     Show all 3 Subjects
Abstract:
... Filtering in the spherical harmonic domain has become a common practice for the post-processing of GRACE temporal gravity field solutions. The most frequently used filtering technique to suppress correlated errors in GRACE data is the isotropic Gaussian averaging filter. In this study, we revisit the methods for calculating isotropic Gaussian filter coefficients (i.e., forward recurrence relation ...
DOI:
10.1016/j.cageo.2019.07.007

2. The Influence of Gravity on Contact Angle and Circumference of Sessile and Pendant Drops has a Crucial Historic Aspect

Author:
Gulec, Semih; Yadav, Sakshi; Das, Ratul; Bhave, Vaibhav; Tadmor, Rafael
Source:
Langmuir 2019 v.35 no.16 pp. 5435-5441
ISSN:
1520-5827
Subject:
gravity,   etc   ; contact angle; magnetism;     Show all 3 Subjects
Abstract:
... Normally, pendant drops adapt contact angles that are closer to 90° than their sessile analogues. This is due to the drop’s weight that pulls the pendant drop and straightens its contact angles. In this paper, we show a case in which the opposite happens: sessile drops that adapt contact angles that are closer to 90° than their pendant analogues. To achieve these peculiar states, one needs to incr ...
DOI:
10.1021/acs.langmuir.8b03861

3. Experimental investigation on the performance of a double-cylinder flow-induced vibration (FIV) energy converter

Author:
Arionfard, Hamid; Nishi, Yoshiki
Source:
Renewable energy 2019 v.134 pp. 267-275
ISSN:
0960-1481
Subject:
center of gravity; gravity,   etc   ; energy conversion; renewable energy sources; vibration;     Show all 5 Subjects
Abstract:
... In this study, the performance of a double cylinder flow-induced vibration (FIV) energy converter is experimentally investigated. The central aim is to take advantage of drag force and gap flow to enhance the vibration. The cylinders are free to rotate around a pivot and located in different configurations including both cylinders on the downstream, both on the upstream, a cylinder on each side an ...
DOI:
10.1016/j.renene.2018.11.022

4. The effect of fabric mass per unit area and blood impact velocity on bloodstain morphology

Author:
Dicken, L.; Knock, C.; Carr, D.J.; Beckett, S.
Source:
Forensic science international 2019 v.301 pp. 12-27
ISSN:
0379-0738
Subject:
gravity,   etc   ; blood; cotton; fabrics; yarns;     Show all 5 Subjects
Abstract:
... This paper discusses the effects of thickness, mass per unit area, sett, yarn linear density and twist of calico fabrics (100% cotton, plain woven) on the morphology of passive bloodstains. Horse blood was dropped vertically onto three calico fabrics with different mass per unit areas (85.1 g/m², 163.5 g/m² and 224.6 g/m²). Six different impact velocities were used (1.7 ms−1, 2.9 ms−1, 4.1 ms−1, 4 ...
DOI:
10.1016/j.forsciint.2019.05.001

5. Lithofacies architecture of gravel-wave deposits: Insights into the origins of coarse-grained gravity-flow deposits

Author:
Ito, Makoto
Source:
Sedimentary geology 2019 v.382 pp. 36-46
ISSN:
0037-0738
Subject:
gravity,   etc   ; gravel; hydrodynamics; models; sandstone;     Show all 5 Subjects
Abstract:
... Several models of the formation of coarse-grained gravity-flow deposits have been proposed and used in the description and hydrodynamic interpretation of conglomerates and pebbly sandstones in deepwater sedimentary successions. These sediments are considered to have been formed by the interaction between the tractional and suspension processes that are generated by flow deceleration and/or flow tr ...
DOI:
10.1016/j.sedgeo.2019.01.004

6. The contact detection for heart-shaped particles

Author:
Li, Chengbo; Peng, Yixue; Zhang, Peng; Zhao, Chuang
Source:
Powder technology 2019 v.346 pp. 85-96
ISSN:
0032-5910
Subject:
gravity,   etc   ; algorithms; differential equation; powders;     Show all 4 Subjects
Abstract:
... The contact detection between non-spherical particles is an important issue in the discrete element method (DEM). The non-spherical particles commonly used in DEM are ellipsoids or super-ellipsoids. Such particles possess convex shape functions. The determination of contact points can be reduced to a set of nonlinear partial differential equations by the Lagrange method. Then, the Newton-Raphson m ...
DOI:
10.1016/j.powtec.2019.01.079

7. ac/dc Magnetic Fields for Enhanced Translation of Colloidal Microwheels

Author:
Disharoon, Dante; Neeves, Keith B.; Marr, David W. M.
Source:
Langmuir 2019 v.35 no.9 pp. 3455-3460
ISSN:
1520-5827
Subject:
gravity,   etc   ; friction; magnetic fields; microscopy;     Show all 4 Subjects
Abstract:
... Microscale devices must overcome fluid reversibility to propel themselves in environments where viscous forces dominate. One approach, used by colloidal microwheels (μwheels) consisting of superparamagnetic particles assembled and powered by rotating ac magnetic fields, is to employ a nearby surface to provide friction. Here, we used total internal reflection microscopy to show that individual 8.3 ...
DOI:
10.1021/acs.langmuir.8b04084

8. RRT-based path planning for an intelligent litchi-picking manipulator

Author:
Cao, Xiaoman; Zou, Xiangjun; Jia, Chunyang; Chen, Mingyou; Zeng, Zeqin
Source:
Computers and electronics in agriculture 2019 v.156 pp. 105-118
ISSN:
0168-1699
Subject:
gravity,   etc   ; Litchi; algorithms; models; planning;     Show all 5 Subjects
Abstract:
... Aiming to realize the obstacle avoidance of the litchi-picking robot in dynamic and unstructured environments, an improved rapidly exploring random tree (RRT) algorithm is presented in this study. By establishing the collision detection model of the manipulator and obstacles, the obstacle avoidance path planning is carried out. The idea of target gravity was adopted to accelerate the path search s ...
DOI:
10.1016/j.compag.2018.10.031

9. Survey of the near wake of an axial-flow hydrokinetic turbine in the presence of waves

Author:
Lust, Ethan E.; Flack, Karen A.; Luznik, Luksa
Source:
Renewable energy 2020 v.146 pp. 2199-2209
ISSN:
0960-1481
Subject:
gravity,   etc   ; hydrodynamics; kinetic energy; models; particle image velocimetry; surveys; tides; turbines;     Show all 8 Subjects
Abstract:
... Flow field results are presented for the near-wake of an axial-flow hydrokinetic turbine in the presence of surface gravity waves. The turbine is a 1/25 scale, 0.8 m diameter, two bladed turbine based on the U.S. Department of Energy's Reference Model 1 tidal current turbine. Measurements were obtained in the large towing tank facility at the U.S. Naval Academy with the turbine towed at a constant ...
DOI:
10.1016/j.renene.2019.08.067

10. Dispersion of Tracers in the Stable Atmosphere of a Valley Opening onto a Plain

Author:
Quimbayo-Duarte, Julian; Staquet, Chantal; Chemel, Charles; Arduini, Gabriele
Source:
Boundary-layer meteorology 2019 v.172 no.2 pp. 291-315
ISSN:
0006-8314
Subject:
gravity,   etc   ; theoretical models; tracer techniques; urbanization;     Show all 4 Subjects
Abstract:
... We quantify the impact of a valley-wind system on the transport of passive tracers in the stably-stratified atmosphere of a valley dynamically decoupled from the atmosphere above. The simple configuration of an idealized Alpine-type valley opening onto a plain is considered, for two values of the initial buoyancy frequency and of the valley steepness. The valley-wind system consists of thermally-d ...
DOI:
10.1007/s10546-019-00439-2

11. Two-site colloid transport with reversible and irreversible attachment: Analytical solutions

Author:
Katzourakis, Vasileios E.; Chrysikopoulos, Constantinos V.
Source:
Advances in water resources 2019 v.130 pp. 29-36
ISSN:
0309-1708
Subject:
gravity,   etc   ; colloids; porous media; water resources;     Show all 4 Subjects
Abstract:
... Analytical solutions for colloid transport in water saturated, one-dimensional, homogeneous porous media, under fully developed uniform flow are presented. The colloids can be either suspended in the aqueous phase or attached reversibly and/or irreversibly onto the solid matrix. Both attachment rates are assumed linear, and any possible blocking or ripening effects are neglected. The colloids can ...
DOI:
10.1016/j.advwatres.2019.05.026

12. Design and evaluation of surface irrigation systems applying an analytical formula in the irrigation district 085, La Begoña, Mexico

Author:
Chavez, Carlos; Fuentes, Carlos
Source:
Agricultural water management 2019 v.221 pp. 279-285
ISSN:
0378-3774
Subject:
gravity,   etc   ; furrows; irrigation scheduling; surface irrigation; Mexico;     Show all 5 Subjects
Abstract:
... The area under irrigation in Mexico is just over 6.64 million hectares, most of which is irrigated with surface gravity systems (borders or furrows). However, one of the main problems presented by these methods is the loss associated with deep infiltration, tailwaters, and flooding in some parts of the land as a result of a poor flow design at the entrance of the furrow or border. In this study, t ...
DOI:
10.1016/j.agwat.2019.04.027

13. Nanotextured Surfaces with Underwater Anisotropic Sliding Resistance for Oil Transfer and Coalescence

Author:
Yang, Xiaolong; Liu, Ziai; Liu, Xin; Song, Jinlong
Source:
Colloids and surfaces 2019 pp. 123691
ISSN:
0927-7757
Subject:
gravity,   etc   ; alkalinity; anisotropy; droplets; equations; oils; oxidation;     Show all 7 Subjects
Abstract:
... Underwater oil droplet manipulations have attracted considerable attentions due to the increasing need of miniature organic reactions. In this work, nanotextured surfaces (underwater superoleophobic) patterned with smooth regions (underwater oleophilic) was prepared via simple through-mask alkalinity oxidation. Relationship between underwater sliding resistance of oil droplets and the pattern shap ...
DOI:
10.1016/j.colsurfa.2019.123691

14. Inverted vortex fluidic exfoliation and scrolling of hexagonal-boron nitride

Author:
Al-Antaki, Ahmed Hussein Mohammed; Luo, Xuan; Alharbi, Thaar M. D.; Harvey, David P.; Pye, Scott; Zou, Jin; Lawrance, Warren; Raston, Colin L.
Source:
RSC advances 2019 v.9 no.38 pp. 22074-22079
ISSN:
2046-2069
Subject:
gravity,   etc   ; boron nitride; green chemistry; solvents;     Show all 4 Subjects
Abstract:
... Exfoliation or scrolling of hexagonal boron nitride (h-BN) occurs in a vortex fluidic device (VFD) operating under continuous flow, with a tilt angle of −45° relative to the horizontal position. This new VFD processing strategy is effective in avoiding the build-up of material that occurs when the device is operated using the conventional tilt angle of +45°, where the h-BN precursor and scrolls ar ...
DOI:
10.1039/c9ra03970h

15. The influence of granular segregation on gravity-driven particle-fluid flows

Author:
Larcher, Michele; Jenkins, James T.
Source:
Advances in water resources 2019 v.129 pp. 365-372
ISSN:
0309-1708
Subject:
gravity,   etc   ; diameter; energy; temperature; water resources;     Show all 5 Subjects
Abstract:
... We phrase and solve boundary-value problems for the segregation of spheres with either equal density and different sizes, or the same size and different densities in flows of a clear fluid driven by gravity over an inclined, erodible bed in a wide channel. We assume that the flow is steady and uniform, collisions between particles dissipate little energy, and the sizes and masses of the particles ...
DOI:
10.1016/j.advwatres.2017.07.025

16. CFD and DEM modelling of particles plugging in shale pores

Author:
Yang, Xianyu; Chen, Shuya; Shi, Yanping; Feng, Ruimin; Cai, Jihua; Jiang, Guosheng
Source:
Energy 2019 v.174 pp. 1026-1038
ISSN:
0360-5442
Subject:
gravity,   etc   ; models; nanoparticles; particle size; roughness; shale;     Show all 6 Subjects
Abstract:
... Nanoparticles plugging effect has recently been recognized in shale cores. However, the motional discipline and plugging efficiency of different nanoparticles in shale pores have not been well recognized. In this paper, an approach with CFD and DEM to model particulate suspension flows is presented in the micro scale for shale pores. The particle trajectory and the plugging efficiency can be obtai ...
DOI:
10.1016/j.energy.2019.03.050

17. Analytics of planetary rotation: Improved physics with implications for the shape and super-rotation of Earth's core

Author:
Criss, Robert E.
Source:
Earth-science reviews 2019 v.192 pp. 471-479
ISSN:
0012-8252
Subject:
gravity,   etc   ; energy conservation; equations; geophysics; models;     Show all 5 Subjects
Abstract:
... The basis of the famous equation attributed to Maclaurin (1742), which relates the ellipticity of homogeneous spheroids to their rotation rate, is reviewed and Todhunter's (1873) neglected but important contribution is recognized. The relationship is then re-derived in a new manner based on potentials and energy conservation rather than on force balance, yielding exact analytical equations that ar ...
DOI:
10.1016/j.earscirev.2019.01.024

18. Gravity-Wave Drag in the Stable Boundary Layer Over Moderate Terrain

Author:
Lapworth, A.; Osborne, S. R.
Source:
Boundary-layer meteorology 2019 v.171 no.2 pp. 175-189
ISSN:
0006-8314
Subject:
gravity,   etc   ; hills; landscapes; models; topography; troposphere; valleys;     Show all 7 Subjects
Abstract:
... Two previous studies of vertical stress profiles due to gravity waves in the stable boundary layer have given differing results. The current study uses a high-resolution numerical forecast model to determine the effect of moderate topography on the vertical stress profile due to gravity waves in the stable boundary layer. The results show that while a quadratic stress profile is expected when topo ...
DOI:
10.1007/s10546-018-00422-3

19. Blooming of Block Copolymer Micelles into Complex Nanostructures on a Surface

Author:
Zhu, Hongyan; Wang, Xinyan; Cui, Yan; Cai, Jiandong; Tian, Feng; Wang, Jie; Qiu, Huibin
Source:
Macromolecules 2019 v.52 no.9 pp. 3479-3485
ISSN:
1520-5835
Subject:
gravity,   etc   ; annealing; composite polymers; micelles; nanomaterials; solvents;     Show all 6 Subjects
Abstract:
... Self-assembled block copolymer (BCP) nanostructures are of important utility across a wide field. Here, we report a solution–surface sequential self-assembly approach to tailor amphiphilic BCPs in solution and subsequently on a substrate into complex nanostructures. Spherical micelles that formed in solution transform on a substrate sequentially into toroidal micelles, concentric toroidal micelles ...
DOI:
10.1021/acs.macromol.9b00197

20. Helically-driven granular mobility and gravity-variant scaling relations

Author:
Thoesen, Andrew; McBryan, Teresa; Marvi, Hamidreza
Source:
RSC advances 2019 v.9 no.22 pp. 12572-12579
ISSN:
2046-2069
Subject:
gravity,   etc   ; glass; modulus of elasticity; wheels;     Show all 4 Subjects
Abstract:
... This study discusses the role and function of helical design as it relates to slippage during translation of a vehicle in glass bead media. We show discrete element method (DEM) and multi-body dynamics (MBD) simulations and experiments of a double-helix Archimedes screw propelled vehicle traveling in a bed of soda-lime glass beads. Utilizing granular parameters from the literature and a reduced Yo ...
DOI:
10.1039/c9ra00399a